SharePoint Online Workflow in Office 365 cannot send emails to Distribution Lists. A few of my colleges have come across this issue when dealing with workflows in O365.
This information is widely enabled and there are a few blogs about it like - https://askmanisha.wordpress.com/2016/01/19/send-emails-to-distribution-lists-using-sharepoint/
So what you need is a mail enabled security group.
But wait, there is another piece to the puzzle which often stumps people. This mail enabled security group needs at least read-only access to the site where workflow is.
There you go, now you can successfully have workflows mailing stuff.
To summarize, two things required for workflow to send mail -
1. Mail enabled security group
2. Mail enabled security group having at least read-only permissions to the site.
This information is widely enabled and there are a few blogs about it like - https://askmanisha.wordpress.com/2016/01/19/send-emails-to-distribution-lists-using-sharepoint/
So what you need is a mail enabled security group.
But wait, there is another piece to the puzzle which often stumps people. This mail enabled security group needs at least read-only access to the site where workflow is.
There you go, now you can successfully have workflows mailing stuff.
To summarize, two things required for workflow to send mail -
1. Mail enabled security group
2. Mail enabled security group having at least read-only permissions to the site.
